<!DOCTYPE HTML>
<html>
<head>

    <meta charset="UTF-8">
    <title>My WebSocket</title>

    <style>
        #message {
            margin-top: 40px;
            border: 1px solid gray;
            padding: 20px;

        }

    </style>
</head>
<body>
<button onclick="connectWebSocket()">连接WebSocket</button>
<button onclick="closeWebSocket()">断开连接</button>
<hr/>
<br/>
消息：<input id="text" type="text" />
接收者：<input id="toUser" type="text" />
<button onclick="send()">发送消息</button>
<div id="message"></div>
</body>
<script type="text/javascript">

    let websocket = null;

    function connectWebSocket() {
        //这里需要的路径需要配置相对应的路径
        const target = "ws://localhost:8081/chat/webSocket/1/6";

        //判断当前浏览器是否支持WebSocket
        if ('WebSocket' in window) {
            websocket = new WebSocket(target);
        } else {
            alert('Not support websocket')
        }
        //连接发生错误的回调方法
        websocket.onerror = function () {
            setMessageInnerHTML("error");
        };
        //连接成功建立的回调方法
        websocket.onopen = function (event) {
            setMessageInnerHTML("Loc MSG: 建立连接");
        }
        //接收到消息的回调方法
        websocket.onmessage = function (event) {
            setMessageInnerHTML(event.data);
        }
        //连接关闭的回调方法
        websocket.onclose = function () {
            setMessageInnerHTML("Loc MSG:关闭连接");
        }
        //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
        window.onbeforeunload = function () {
            websocket.close();
        }
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket() {
        websocket.close();
    }

    //发送消息
    function send() {
        //获取输入的文本信息进行发送
        const msg = document.getElementById('text').value;
        const toUser = document.getElementById('toUser').value;
        const chatMsg = {content: msg, toUser: toUser};

        websocket.send(JSON.stringify(chatMsg));
    }
</script>
</html>
